Page 170 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Object Oriented Analysis and Design

Notes Public protocols define the functionality and external messages of an object, while private
protocols define the implementation of an object.

13.4 Keywords

Axiom: An axiom is a fundamental truth that always is observed to be valid and for which there
is no counter example or exception.
Corollary: A corollary is a proposition that follows from an axiom or another proposition that
has been proven.
Coupling: Coupling is a measure of the strength of association established by a connection from
one object or software component to another.

Inheritance coupling: Inheritance coupling is a form of coupling between super-and sub-classes.
Interaction coupling: Interaction coupling involves the amount and complexity of messages
between components.

Private protocols: Private protocols define the implementation of an object.
Public protocols: Public protocols define the functionality and external messages of an object.
Theorem: A theorem is a proposition that may not be self-evident but can be proved from
accepted axioms.

13.5 Review Questions

1. What are the axioms of object-oriented design? Discuss.
2. What are corollaries? Draw the diagram to show origin of corollaries and explain.

3. Describe the concept of coupling.
4. Make distinction between interaction coupling and inheritance coupling.
5. Illustrate the concept of class design.
6. Elucidate the process of achieving multiple inheritance in a singe inheritance system.
7. Discuss the concept of public, private and protected protocols.

8. Analyze whether public protocol layer is external or internal.
9. Explain the concept of refining attributes.
10. What is an attribute presentation recommended by UML? Discuss.

Answers: Self Assessment

1. Axiom 2. Theorem

3. corollary 4. Coupling
5. Coupling 6. Interaction
7. Inheritance 8. Class cohesion
9. class designer 10. Public

11. Private 12. Class

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